REPORT ON THE CRINOIDEA. 189 
case with some of the following extinct forms,” viz., Cystidea, Edriasterida, and 
Blastoidea. 
The difference in the functions of the water-vascular system between the stalked and 
the unstalked Echinoderms respectively was applied by Prof. Ray Lankester for 
systematic purposes in his division of the Echinoderms into Ambulacralia and Tenta- 
culata, the latter including Crinoids, Cystids, and Blastoids." 
The name “ Tentaculata” is unfortunately open to the objection that even in recent 
Crinoids some of the radial water-vessels may be totally unprovided with tentacles at their 
sides ; while if, as I believe, the water-vessels of the Blastoids occupied the subambu- 
lacral canals within the lancet-pieces,” they must certainly have been non-tentaculate. 
To one division (class) of the group, therefore, the name “Tentaculata” would not be at 
all applicable. Neither do I like the extension of the term “ Crinoidea” to the Blastoids 
and Cystids, and the consequent limitation of the brachiate forms by the name 
Eucrinoidea, which we owe to Zittel so far as I have been able to trace it; though it has 
recently been adopted by de Loriol. 
In Miller's original definition of the Crinoidea* he described them as having 
like body containing the viscera, from whose upper rim proceed five articulated arms, 
divided into tentaculated fingers more or less numerous.” The presence of these arms is 
essential to the idea of a “lily-shaped animal.” The very characteristic appearance of 
the Crinoid type is lost if the arms be not attached to the calyx; while morphologically 
they are of the utmost importance. 
On the other hand, joimted appendages of this kind, attached to the rim of the cup, 
and containing radial extensions of the nervous axis of the stem, as well as of all the 
ambulacral structures which surround the peristome, together with the genital glands, are 
entirely absent both in the Blastoids and in the Cystids. In the former group, it is 
true, there were jointed appendages at the sides of the ambulacra; but although the 
latter are very often spoken of as “recumbent arms,” they are not composed of articulated 
pieces, and only a very general homology can be traced between them and the branching 
arms of a Crinoid. In the Cystids, however, segmented arms somewhat like those of 
Crinoids seem to have been occasionally present, and even grooved by the ambulacra. 
But they were mostly attached somewhat irregularly in the neighbourhood of the mouth, 
and not to the radial portions of the cup as in the Crinoids ; and I much doubt whether 
their component segments were regularly articulated together. 
Neither the Blastoids nor the Cystids, therefore, can properly be classed as Crinoidea, 
in the sense of Miller’s definition of the group; though this has been very frequently 
done during the last forty years, more especially by continental naturalists. Von 
ce 
a cup- 
1 Notes on Embryology and Classification, Quart. Journ. Micr. Sci., 1877, vol. xvii., N. §., p. 444. 
2 On Certain Points in the Morphology of the Blastoidea, Ann. and Mag. Nat. Hist., 1881, ser. 5, vol. viii., p. 420; 
Thid., 1882, vol. ix. p. 218. 
3 Op. cit., p. 7. 
